\documentclass{article}
\begin{document}
\[
\frac{\frac{{\forall (p1,\forall (pn,r))}\quad{\exists (pn,pn)}}{\forall (p1,\exists (pn,r))}{AA}\quad{\exists (p1,\forall (pn,\neg r))}}{\exists (p1,\neg p1)}{D3}
\]
\end{document}
